The present invention relates to a novel room temperature cross-linkable aqueous composition and a process for preparing the same, and more particularly to a novel room temperature cross-linkable aqueous composition which can give excellent film properties to materials for which weatherability, durability and the like are required, such as outer walls of buildings, automobiles and household electric appliances, and a process for preparing the same.
In recent years, there have been made some attempts to replace paints and adhesive agents containing an organic solvent with those containing an aqueous solvent from the viewpoint of preventing environmental pollution and saving resources.
Conventional paints and adhesive agents containing an aqueous solvent are, however, remarkably inferior in formed film properties such as weatherability, water resistance and stain resistance to these containing an organic solvent by the following reason. A water-disperible resin is generally used in conventional paints and adhesive agents. The water-disperible resin is prepared by emulsion-polymerization using an ionic or nonionic surfactant. Therefore, the water-disperible resin dose not have a crosslinkable functional group in its molecule and is easily influenced by the surfactant.
Various attempts to solve the above-mentioned defects have been proposed. One of the attempts is using a copolymer which is obtained by emulsion-copolymerizing a vinyl monomer having a hydrolyzable silyl group with other copolymerizable vinyl monomer to improve water resistance and weatherability of a polymer obtained by the emulsion polymerization using an ionic or nonionic surfactant (Japanese Unexamined Patent Publication No. 254116/1988).
However, since the copolymer has trimethoxysilyl group or triacetoxysilyl group as a hydrolyzable silyl group, the copolymer has defects that the copolymer is apt to gelate during preparing an emulsion or being stored and cannot stably be prepared and stored.
An object of the present invention is to provide an aqueous composition having excellent storage stability and excellent room temperature cross-linkability which can be polymerized in stable condition without gelation.
This and the other objects of the present invention will become apparent from the descriptions hereinafter.